Hydrochlorothiazide reduces the swelling and water retention caused by various medical conditions, such as heart, liver, or kidney disease. Lab tests, including kidney function, blood pressure, and electrolyte levels, may be performed while you use Hydrochlorothiazide. The absorption of hydrochlorothiazide from the gut. This medicine should not be taken within four hours of colestipol or cholestyramine, as these medicines may reduce the absorption of hydrochlorothiazide from the gut. Hydrochlorothiazide in pregnancy, thiazide diuretics may cause an increased risk of congenital defects.